Blankholder press for forming workpieces



Aug. 16, 1949. D. R. FRANCIS 2,479,336

BLANKHOLDER PRESS FOR FORMING WORKPIECES 1 Filed March 27, 194'? 2 Sheets-Sheet 1 FIG. 5 64 78 76 I 82 INVENTOR i r BgANIEL ROBERT FRANCIS 74 66 v 4 8o ATTORNEYS Aug. 16, 1949. D. R. FRANCES BLANKHOLDER PRESS FOR FORMING WORKPIECES 2 Sheets-Sheet 2 Filed March 27, 1947 FIG.6

INVENTQR DANIEL ROBERT- FRANCI$ BY 7 77.01.;

ATTORNEYS Patented Aug. 16, 1949 UNITED STATES PATENT o-FFlcE BLANKHOIQDER PRESS uonEoa ING WQBKPIECES Daniel Robert Francis, Mount Gilead, hio',.as'-

signer-rte H-P-M: Development Corporation, Wilmingtom. Del., a. corporation ofv Delaware Application March 27, 1947; seria No". 737,652

This invention relates to an: improved apparatus for formingcylindrical work membersfrom plates.

The particular object of this invention is. to provide an apparatus for forming a plate of material into a cylindrical work member with, a singlestroke: of a press.

A further objectis to provide an apparatus ion formingcylindrical members from plates which first bends the plate into a U-shape and thereafter forms theleg portions thereof over to. form a completed; cylinder," and; accomplishes this by asingle stroke of a press member.

It is also an object of; this invention to adapt a blankholder type'press to theoperation of forming a cylinder from fiat plate material without greatly modifying the structurev thereof.

A still further object is to provide; incombination with a blankholder type press, an improved die arrangement whereby the workpieces may readily beremoved'fi'om the press following the forming operation.

These and other objects andladvantages. will become more apparent upon reference to the foi lowing description. and: the accompanying drawings in. which:

Figure 1 is a vertical section throughv a press constructed according to this invention;

Figures 2, 3, and'4 are fragmentary views showing thelpress andworkpiece being formed thereby. in various stages of 'a work cycle;

Figure 51 is a plan'section indicated by theline 55. on. Figure I; and

Figure 6 is a view showing the use of a positive stop to halt: the blank-holder in a predetermined position.

Referring to Figure 1, a press according-,to-this invention comprises a'bed HI and'a head i2which are interconnected bystrain rods [4. A platen I6 is reciprocable to and from the bed It) and may be guided on the strain rods [4, if desired.

Connected with the platen I6 is a double acting ram l8 which reciprocates in a cylinder carried by the head l2.

Suspended beneath the platen I6 is a blankholder platen 22, the spacing of which relative to the platen is limited by the rods 24. Secured to the blankholder platen 22 and extending into the cylinders 2'6 in the platen 16 are the blankholder plungers 28. When the platens l6 and I2 move toward each other the plungers 28 displace fluid from the cylinders 26 through the conduit 30. The conduit 30 is connected with a valve 32 that normally places the said conduit in communication with a second conduit 34 leading 1 Claim. (01. 15349) to the reservoir 36"- mounted on the press headi- Freeflowof fluidfrom the reservoir into" the conduit 34 is provided for by the check valve-38' while fluid flow from the conduit 34--into means 3'6"i's'- controlled'by the adjustable pressure relief valve Ml. It will beapparent that separating= movements ofthe platens l6 and' 22 may be hadfreely at anytime whereas movements thereof together are resisted bythe-pressure de velop'cd in. thecylinders- 2 6 by the relief valve" ME A- thirdconduit His connected with thevalv'e 32 andopens directly into the reservoir 36L The conduit 42 is adapted for being connected with theconduitw when thevalve member Mlof the said valve'is moved rightwardly against the" thrust of the spring 45 by engagement with thevalve member ofthe cam 48' securedto theplaten lG-I 'Dhe purpose of this Will become more apparent hereinafter. T

The double acting ram' l8has connected therewith" a: fluid source 50- adapted for selectively supplying fluid tothe advancing and retracting sides of the s'aid ram: for reciprocating the same toether. with theplatens l6 and 2-2. The" source 501 is: normally urged-by a spring 52- to deliver through the conduit 54. to the retracting sideof the ram, and' when the solenoid- 55 is actuated; the: fluidisource -is shifted to deliver through-the conduittEB to: the advancing side oithe mm IS;

AS': best seenin Figures 2; 3 and 4; there" is mountedv on the press beda, die comprising thefsu'bstantially semi-cylindrical groove 62. Sus pendedi from. the" blankholc'ier platen is a-' sub stantia1ly=cylindricalarbor 64' which isadapted for entering the groove 62 with sufficient space therearoundito receive the thickness of'the worlr member 65. Extending downwardly from the maimplaten lfi thereis a die member 6'8- having a. substantially semi-cylindrical groove" 10 therein which is complementary to the groove 62 in the die member 60.

The arbor 64 is carried on the blankholder platen 22 as shown in Figure 1 wherein it will be seen that the right hand support for the said arbor comprises a pivot 12 while the left-hand end comprises the abutment T4. The pivot '2 permits the arbor 64 to be turned in order to permit the formed workpieces to be removed therefrom.

As shown in Figure 5, the arbor 64 may carry a fluid operable plunger 16 which has an end portion 18 thereon adapted for engaging and stripping the workpiece from the arbor. Conveniently, the valve mechanism for actuating the plunger 16 in its stripping and return movements may be located, as indicated at 80, about the pivot I2 whereby movement of the arbor to its unloading position will effect fluid communication between the pressure conduit 82 and the side of the plunger 16 on the right side as viewed in Figure 5.

Operation In operation, the workpiece 66, which is a flat plate of metal, is placed on the die 60, as shown in Figures 1 and 2. Thereafter, the solenoid B is energized to commence the delivery of fluid from the source 50 to the advancing side of the 'ram 12. This moves the ram and platens l6 and 22 downwardly and brings the arbor 64 in engagement with the workpiece 66 as shown in Figure 3. At this time the workpiece is formed substantially to a U-shape with the edge portions thereof extending vertically as indicated at 34.

It will be noted that the edges of the groove in the die member 63 are somewhat relieved as at 86 so that further movement of the said die member will move the portions 84 of the Work member inwardly,

Proceeding from Figure 3 to Figure 4, wherein the die member 68 has been advanced to the limit of its travel, it will be seen that the workpiece 66 has been completely formed into a cylindrical member. It will be observed that between their Figures 3 and 4 positions, the platens l6 and 22 have moved relatively. If, during this relative movement, the valve 32 is inoperative due to its position relative to the cam 48, the relative movement of the blank-holder platen, relative to the main platen, will be accompanied by a discharge of fluid through the relief valve 40 which will develop a continuous pressure downwardly on the blankholder platen and mandrel 641. If the workpiece being formed is of a material having a substantial amount of spring-back, the press will preferably be operated in this manner in order to insure the proper engagement of the edges of the work member by the upper die.

However, if the material being formed is relatively ductile and the bending thereof is not accompanied by an appreciable amount of spring-back, then the valve 32 may be made operative and will connect the blankholder cylinders 26 to exhaust at or shortly after the time the press reaches its Figure 3 position. In this manner, the remainder of the working stroke of the platen l6 may be accomplished without any loss of pressing force to the blankholder platen.

After the workpiece is fully formed and the press platens have been retracted, the mandrel 64 is rotated about its pivot 12. The rotating movement of the mandrel on its pivot making connection between the conduit 82 and plunger 16 actuates the plunger to move the stripper 118 to '4 dislodge the formed workpiece from the mandrel. After the workpiece has been dislodged, the mandrel is returned to its working position and the plunger 16 and stripper 18 automatically return to their Figure 5 position.

From the foregoing it will be seen that this inventionprovides an apparatus for ye rapidly forming cylinders from fiat plates or she ts. Furthermore, this is accomplished by a sin le stroke 'of the press platen so that only one press and one set of dies are required for the complete operation.

As shown in Figure 6, the blank-holder platen 22 may have a stop member 88 thereon which abuts the die member and prevents the thrust of the blank-holder plungers from being exerted on the thin metal of the workpiece.

It will be understood that this invention is susceptible to modification in order to adopt it to diiTerent usages and conditions and, accordingly, it is desired to comprehend such modifications within this invention as may fall Within the scope of the appended claim.

I claim:

In a press; a pressing platen having a grooved die thereon; a, similarly grooved die stationarily mounted; a blank-holder platen suspended from said pressing platen; piston-cylinder means extending between said platens and adapted for exerting a thrust on said blank-holder platen in response to movement of said pressing platen there-toward; a mandrel carried by said blankholder platen between said' dies; and pivot means supporting said mandrel on said blankholder platen to permit movement thereof for loading and unloading, said mandrel having stripper means to remove workpieces formed thereon and automatically operable by the movement of said mandrel about its pivot.

DANIEL ROBERT FRANCIS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 380,017 Hall Mar. 2'7, 1888 1,379,078 C'arlsen Sept, 27, 1932 1,941,953 Pump Jan. 2, 1934 2,158,176 Dewey May 16, 1939 2,167,941 Ernst Aug. 1, 1939 2,192,778 Stacy Mar. 5, 1940 2,302,953 Pocock Nov. 24, 1942 FOREIGN PATENTS Number Country Date 584,593 Germany 1933 711,516 France -1 1931 

